Developing device



June 1, 1965 M. H. DE BELDER DEVELOPING DEVICE 2 Sheets-Sheet 1 Filed Aug. 8, 1962 INVENTOR [Z4 write ficiarjiah'ez;

W I M M i ATTORNEYfi June 1, 1965 M. H DE BELDER DEVELOPING DEV'ICE 2 Sheets-Sheet 2 Filed Aug. 8, 1962 INVENTOR Ah 1022': flaw kieher My M K/ZZW ATTORNEY$ United States Patent 0 3,186,325 DEVELUPENG DEVICE Maurice Hector De Eelder, Mechlin, Eelgium, assiguor to Gcvaert Plioto-Froducten N.V., Mortscl, Belgium, a Belgian company Filed Aug. 8, 1%2, Ser. No. 215,677 Claims priority, application Belgium, Aug. 9, 1961, 40,872, Patent 607,401 11 Claims. (Cl. 95-39) The present invention relates to a process and apparatus for obtaining prints according to the silver complex diffusion transfer process.

More especially the invention relates to a process and apparatus for the exact positioning of the silver halide emulsion layer bearing negative support, in relation to the receiving support.

For producing prints according to the known silver complex diffusion transfer process, a silver halide emulsion layer bearing negative, hereinafter called emulsion support, after its image-wise exposure and treatment with a developing solution for the silver halide, is pressed against a so-called receiving support in the presence of a solvent for the silver halide; with the supports so positioned the silver halide which was not converted into silver, diffuses from the emulsion support to the receiving support where it is reduced to a silver image adhering to the surface of. the receiving support. If an exact positioning of the image on the receiving support has to be obtained, it is necessary to effect precisely correct positioning of the emulsion support in relation to the receiving support during the diffusion transfer step.

An apparatus for accurately positioning the emulsion support in relation to the receiving support is among others described in the German model of utility 1,822,804. In this apparatus, the positioning of the'two supports in a transverse direction is accomplished by means of spaced side guide members. The positioning of the supports in a longitudinal direction is effected by simultaneously introducing both supports between a pair of pressure rollers at the entrance of the developing bath. There are, however, dimculties in exactly reproducing this operation, as on the one hand, a high level of precision is required by the operator in sliding both supports simultaneously between the pressure rollers and, on the other hand, no device is provided for assuring that the support pass through the bath in a reproducible manner.

Another device allegedly useful for the exact positioning relative to one another of two supports, which have to be pressed against each other between two rollers after a given treatment, is described in the German patent specification 1,102,558. In this apparatus, a pair of entrance rollers are provided at the entrance to a plurality of spaced apart guide plates defining a channel through the solvent bath for the supports.

The rollers are mounted at one end of fulcrumed levers and the stop elements adjacent the other end so that separation of the rollers during introduction of the superposed supports projects the stop elements into the channel. The levers are spring-biased to separate the rollers and latch means is provided to hold the rollers together against the force of the biasing spring. The array of levers, rollers and stop element thus have two positions, one in which the entrance rollers are pressed to each other for gripping and conveying the two supports, and the others in which they are removed from each other to allow the free passage of the two supports between them up to the limit of the stop elements. The disadvantage of this apparatus resides in the critical transition between the removal of the stop elements from the path of the supports and positive engagement thereofby the pressing of the rollers. If, the pressing of the rollers does not take place 3,185,325 Patented June 1, 1965 at the moment that the stop elements clear the passage, which is difficult to achieve mechanically either the supports are sliding freely over some distance in the apparatus, especially if one or more of the rollers are positively driven or otherwise the front edge of the supports is partly distorted by abutment against the stop elements. In both cases, a correct positioning of both supports of the desired precision relative to each other is impossible.

Now a process has been found for the manufacture of prints according to the silver complex diffusion transfer process, comprising introducing and guiding an emulsion support and a receiving support between guide plates and between a displaceable driven pair of ingress rollers in opened position to a developing bath, positioning the emulsion support in longitudinal direction relative to the receiving support by causing both supports to abut at their front edges against at least one displaceable blocking element which blocks the passageways of the supports between the guide plates before they reach the developing bath, driving the supports by closing the movable driven pair of ingress rollers whereby the supports are engaged and moved through the developing bath, pushing with their front edges the said displaceable blocking elements out of their passageway between the guide plates.

Hereinafter the present invention is described by way of an example with reference to the accompanying drawings.

FIG. 1 represents a schematic longitudinal section of the device according to the present invention.

FIG. 2 represents a detailed view of the entrance roller pair and the set of blocking elements.

FIG. 3 is a detailed view of the developing bath.

, FIG. 1 represents a device for the manufacture of prints according to the silver complex diffusion transfer process consisting of a developing tank 1, a pair of ingress rollers 2, 3, a pair of egress rollers 4, 5 and guide plates 6, 7, 8. These guide plates guide an emulsion support 9, and a receiving support it), respectively through the device.

According to the invention, the device is provided with a set of stop fingers 13 which can be removed from the passagewayof the supports after these supports have been gripped by the ingress rollers.

This set of stop elements can take two stable positions which are assured by a bistable spring system 15.

The upper ingress roller 3 is mounted for free rotation on a set of arms 14 which are moved by an actuating ieans hereinafter described so that the roller 3 can press against roller 2 or be separated therefrom. Lower ingress roller 2 is driven at a constant speed by means not shown so that its peripheral speed is equal to the peripheral speed of the outlet rollers 4 and 5. The entrance rollers are adapted to press both supports 9 and 16 against each other by movement through the openings 17, 18, i9 and 29 provided for this purpose in the guide plates 6, 7, 8, respectively. The set of blocking elements 13 is controlled by a bistable spring system (shown in detail in FIG. 2). A springlfi is attached to the set of stop elements at point 24. It will be obvious from the drawing that the set of stop elements 13 is capable of pivotable movement about axis 25 between two positionsa closed position (shown in solid lines in FIG. 2) with the lower extremities of the elements projecting into the passageways between the guide plates to limit the travel of the supports within the passageways and an open position (shown in dotted lines in FIG. 2) with such extremities retracted from the passageways to allow the supports to travel unimpeded. The point of connection of the upper end of spring 15 is so disposed with respect to axis 25 and point 24 that the spring functions in the nature of a toggle or over-center spring, biasing theelements to 3 one or the other of such positions and maintaining the same in a stable condition thereat. The location of elements 13 at the two positions may be determined by suitably arranged detent means, such as rib 16 carried by guide plate 8, for example, for engagement with the tips of the element at the closed position. For the open position, a surface 27 on the ingress roller supporting lever 1 itself may act as a detent, being disposed when the roller 3 is moved into contact with roller 2, to engage an extension of elements 13 when the latter pivot to open position.

A number of pressure rollers 11 and 12. are provided in the developing bath, the journals thereof being held for free bodily movement in a generally vertical direction by upwardly opening grooves 22 (FIG. 3).

The operation of the device will now be described in detail:

An emulsion support 9, which in the present case is an image-wise exposed silver halide emulsion layer bearing negative, is introduced with its emulsion side facing upwardly into the channel or passageway between .the two lower guide plates '7 and 8 and pushed forward to the limit permitted by the set of stop elements 13. An aluminum offset foil Flu, provided with a number of perforations at its front and back side, is introduced an equal distance into the channel or passageway between the two upper guide plates until stopped by the stop elements 13.

The latter, of course, are in closed position up to this time, the lower extremities thereof projecting into both passageways between the guide plates at at least essentially co-terminous points with their tips engaging rib 16, and are so held by spring 15.

Next, the top ingress roller 3 is lowered towards bottom roller 2, pressing the two supports 9 and it? against each other by way of the openings formed respectively in the guide plates 6, 7 and Both supports are moved forwardly by the driving action of the rollers and in so moving, their front edges will force the set of stop elements 13 to pivot in a clockwise direction. Once the stop elements pivot the short distance required to carry the bistable spring just past dead center, i.e. a straight line passing through axis and the upper point of connection of the spring, the spring force is immediately applied to continue the movement of the element to full open position. In this way, rubbing of the stop elements against the aluminum foil 9 during travel of the supports 9 and it) in the eveloping bath is avoided and any damage to the aluminum foil is prevented.

When both supports arrive in the developing bath they are pressed against the guide plates 7 and 8, respectively, by the rollers ill. and 12. Hereby the supports are forced to follow each a reproducible passageway which is determined by the profile of the respective guide plates.

When both supports have been carried through the developing bath they are gripped by the continuously driven egress rollers 4 and 5. These rollers press the sup ports against each other and the superfluous developing liquid is removed. After a few moments of face-to-face contact, the supports are separated from each other and a positive print is obtained on the aluminum foil. Next, this foil is treated with an appropriate lithographic composition whereupon it is ready for attachment on the pressing roller of an aluminum offset printing press.

Owing to the action of the stop elements at the entrance of the apparatus together with the equal peripheral speeds of the entrance and outlet rollers and of the guide rollers in the developing bath, an exact longitudinal positioning of the emulsion support relative to the receiving support, when they are pressed on each other by the outlet rollers and 5, is always assured. When the device is provided with sidelong guide plates, as is known in the art, which provide exact transverse positioning, the image will always occupy the same place on every aluminum foil. Consequently, separate adjustment of the printing press for each new printing plate becomes quite unnecessary in most applications.

Obviously, when the lever 14 and and top ingress roller 3 are returned to starting position, the set of stop elements will likewise be returned to closed position, the movement of lever 14 carrying the elements through dead center by virtue of the engagement of surface 27 with the element extension, after which the spring force suffices to move the elements the remainder of the way.

According to a modified embodiment this abutment surface 26 may cooperate with a lug 27 provided on the element extension in such a way as to form a locking system. With the length of the lug selected to correspond with the clearance between the surface 27 and the extension, it will be apparent that the elements are fixedly held against any pivotal movement until the top ingress roller is lowered to operative position. Thus, the immobility of the blocking elements in the closed position is completely assured.

The operation of this embodiment proceeds as follows:

When the emulsion support and the receiving support are slipped between the separated ingress rollers against the set of stop elements 13, a solenoid 2 8 is excited. This can be done either by a hand switch or by micro switches which are controlled by the supports. The arm 14 is rocked to the right and the free rotating roller 3 is pressed toward the driven roller 2. The same rocking movement releases the abutment surface 26 from the lug 27, freeing the stop elements 3.3 for pivotal movement by both supports. After both supports are removed from the apparatus the excitation of the solenoid Z8 is interrupted. The arm lid is swung back by the spring 29, the engagement of the surface 2") of the lever i l against the lug 26 resulting in the blocking elements 13 being pivoted again to their closed position. The device is now once more in starting position and ready for another operation. In the starting position of the modified embodiment the surface 2'? maintains pressure against the lug 26 so that the blocking elements 13 are locked, and there is no risk that these blocking elements will be slightly pressed to some intermediate position in case both supports are introduced with. some violence between the separated ingress rollers.

I claim:

1. In an apparatus for contacting an exposed emulsion support and a receiving support in a diffusion transfer operation and including means defining a developing Zone, a plurality of guide plates defining at least one passageway for guiding said supports in generally superposed relationship at least into said zone, and a pair of feed rollers for said supports disposed adjacent the ingress end of such passageway, at least one of said rollers being mounted for bodily movement to and from an operative position cooperating with said other roller to contact said supports and a displaced position for introduction of said supports, and means for positively rotating at least one such roller to advance said supports when said movable roller is in said cooperating position, in combination, the improvement comprising a set of stop fingers mounted on an axis disposed adjacent said plates downstream of said feed rollers for pivotal movement between a closed position at which said fingers project into said passageway to arrest travel of said supports therethrough and an open position at which said fingers are retracted from said passageway to permit free travel of said supports, and bistable biasing means connected to said set of fingers urging the same into either of said two positions after positive movement of said fingers away from the other position and past dead center, whereby said biasing means maintains said set of fingers in closed position to limit the extent of introduction of said supports into said channel, then yields upon positive advance of said supports by said drive rollers and upon movement past dead center transfers said set to open position clear of said supports.

2. The apparatus of claim 1 wherein said axis is disposed on one side of said guide plates and the latter are provided with slots to receive said fingers in said first position.

3. The apparatus of claim 1 wherein the center axis of said bistable biasing means intersects the path of oscillation of at least one extremity of said fingers within said passageway.

4. The apparatus of claim 1 wherein said bistable biasing means is constituted by toggle spring means.

5. The apparatus of claim 1 including detent means engageable by said set of fingers at each of said positions to preclude further pivotal movement thereof.

6. The apparatus of claim 5 wherein the detent means for the second position of said set of fingers is associated with said bodily movable roller for movement therewith and is effective when said roller is in operative position, movement of said roller to displaced position also moving said last-mentioned detent means to initiate return of said set of fingers to first position.

'7. The apparatus as in claim 6 wherein said set of fingers includes an extension adapted .to be engaged by said last-mentioned detent means when said means and the roller with which the same is associated are in displaced position, positively locking said fingers in P jeoted position until the roller is moved to operative position.

8. The apparatus of claim 1 including at least three spaced generally parallel guide plates defining separate parallel passageways for said supports and said set of fingers project into both such passageways at points substantially equidistant from said rollers.

9. The apparatus as in claim 1 wherein said set of fingers in said first position projects generally at right angles to said guide plates and extend in closely spaced, generally tangential relationship to the periphery of at least one of said rollers.

10. The apparatus of claim 1 wherein at least one of said guide plates extends substantially through said zone and including a pair of egress rollers to receive the supports from such plate and one of said egress rollers is coupled to one of said ingress rollers for rotation at a constant peripheral speed.

11. The apparatus of claim 10 wherein each such plate extending substantially through said zone is provided with a pressure roller, at each of a plurality of points spaced along its length.

References Cited by the Examiner.

UNITED STATES PATENTS 824,755 7/06 Sturtevant 271-- X 1,15 6,357 10/ 15 Freeman 271-60 X 2,722,417 1 '1/5 5 Nitchie 271-60 2,792,768 5/57 Ludwig -89 FOREIGN PATENTS 556,794 5/58 Canada.

1,102,558 3/ 61 Germany.

NORTON ANSHER, Primary Examiner.

EMIL G. ANDERSON, Examiner. 

1. IN AN APPARATUS FOR CONTACTING AN EXPOSED EMULSION SUPPORTED AND A RECEIVING SUPPORT IN A DIFFUSION TRANSFER OPERATION AND INCLUDING MEANS DEFINING A DEVELOPING ZONE, A PLURALITY OF GUIDE PLATES DEFINING AT LEAST ONE PASSAGEWAY FOR GUIDING SAID SUPPORTS IN GENERALLY SUPERPOSED RELATIONSHIP AT LEAST INTO SAID ZONE, AND A PAIR OF FEED ROLLERS FOR SAID SUPPORTS DISPOSED ADJACENT THE INGRESS END OF SUCH PASSAGEWAY, AT LEAST ONE OF SAID ROLLERS BEING MOUNTED FOR BODILY MOVEMENT TO AND FROM AN OPERATIVE POSITION COOPERATING WITH SAID OTHER ROLLER TO CONTACT SAID SUPPORTS AND A DISPLACED POSITION FOR INTRODUCTION OF SAID SUPPORTS, AND MEANS FOR POSITIVELY ROTATING AT LEAST ONE SUCH ROLLER TO ADVANCE SAID SUPPORTS WHEN SAID MOVABLE ROLLER IS IN SAID COOPERATING POSITION, IN COMBINATION, THE IMPROVEMENT COMPRISING A SET OF STOP FINGERS MOUNTED ON AN AXIS DISPOSED ADJACENT SAID PLATES DOWNSTREAM OF SAID FEED ROLLERS FOR PIVOTAL MOVEMENT BETWEEN A CLOSED POSITION AT WHICH SAID FINGERS PROJECT INTO SAID PASSAGEWAY TO ARREST TRAVEL OF SAID SUPPORTS THERETHROUGH AND AN OPEN POSITION AT WHICH SAID FINGERS ARE RETRACTED FROM SAID PASSAGEWAY TO PERMIT FREE TRAVEL OF SAID SUPPORTS, AND BISTABLE BIASING MEANS CONNECTED TO SAID SET OF FINGERS URGING THE SAME INTO EITHER OF SAID TWO POSITIONS AFTER POSITIVE MOVEMENT OF SAID FINGERS AWAY FROM THE OTHER POSITION AND PAST DEAD CENTER, WHEREBY SAID BIASING MEANS MAINTAINS SAID SET OF FINGERS IN CLOSED POSITION TO LIMIT THE EXTENT OF INTRODUCTION OF SAID SUPPORTS INTO SAID CHANNEL, THEN YIELDS UPON POSITIVE ADVANCE OF SAID SUPPORTS BY SAID DRIVE ROLLERS AND UPON MOVEMENT PAST DEAD CENTER TRANSFERS SAID SET TO OPEN POSITION CLEAR OF SAID SUPPORTS. 